Tractors equipped with various implements, pavers, compactors, graders, scrapers, and other types of machines are used for modifying substrate material or preparing a substrate for various uses. In the paving context, machines known in the art as cold planers are used to remove an upper layer of paving material often in preparation for placement of a substitute paving material mat. A cold planer is typically equipped with a rotor that breaks paving material into chunks of manageable size, and conveys the removed paving material to a truck for disposal or other use such as for fill material.
Recent decades have seen increased interest in in situ processing and reuse of paving material. Most persons will be familiar with the undesirability of cracked, uneven, and/or potholed road and parking lot surfaces. The economy of reusing paving material in place, without removing it and transporting it elsewhere, will also be apparent to most. So-called recyclers or mixers are in increasing use throughout the world for preparing a new substrate to support a new traffic-bearing paving material mat. In general, a recycler or rotary mixer breaks apart old paving material and mixes the chunks of paving material with underlying substrate, typically soil, to produce a new substrate upon which a new traffic-bearing surface such as for a road or parking lot can be placed. Certain challenges have been observed with recyclers or rotary mixers in relation to achieving a desired composition of the mixed material once processed. Commonly owned U.S. Pat. No. 8,794,869 to Schlenker et al. is directed to a rotary mixer having a rotor chamber that receives a first surface and produces a reclaimed surface. An electronic control module is coupled to a rotor chamber and particle sensor and adjusts a degree of pulverization of reclaimed surface according to a difference between a detected particle size and a desired particle size.